diff --git a/libraries/esp8266/examples/interactive/interactive.ino b/libraries/esp8266/examples/interactive/interactive.ino
new file mode 100644
index 0000000000..bf084c9674
--- /dev/null
+++ b/libraries/esp8266/examples/interactive/interactive.ino
@@ -0,0 +1,91 @@
+
+/*
+  Interactive script meant for debugging only
+  Run it on serial console and keep this source file opened for the list of commands
+  Please configure SSID, PSK and IPAddresses below to fit with your network
+
+  Released to public domain
+*/
+
+#include "ESP8266WiFi.h"
+#include "user_interface.h"
+
+const char SSID[] = "open";
+const char PSK[] = "";
+
+IPAddress staticip(192, 168, 1, 123);
+IPAddress gateway(192, 168, 1, 254);
+IPAddress subnet(255, 255, 255, 0);
+
+void setup() {
+  Serial.begin(115200);
+  Serial.setDebugOutput(true);
+
+  WiFi.mode(WIFI_STA);
+  WiFi.begin(SSID, PSK);
+  Serial.println("connecting");
+  while (WiFi.status() != WL_CONNECTED) {
+    delay(500);
+    Serial.print(".");
+  }
+  Serial.println();
+  Serial.println(WiFi.localIP());
+  Serial.print(
+    "WL_IDLE_STATUS      = 0\n"
+    "WL_NO_SSID_AVAIL    = 1\n"
+    "WL_SCAN_COMPLETED   = 2\n"
+    "WL_CONNECTED        = 3\n"
+    "WL_CONNECT_FAILED   = 4\n"
+    "WL_CONNECTION_LOST  = 5\n"
+    "WL_DISCONNECTED     = 6\n"
+  );
+}
+
+void WiFiOn() {
+  wifi_fpm_do_wakeup();
+  wifi_fpm_close();
+  wifi_set_opmode(STATION_MODE);
+  wifi_station_connect();
+}
+
+void WiFiOff() {
+  wifi_station_disconnect();
+  wifi_set_opmode(NULL_MODE);
+  wifi_set_sleep_type(MODEM_SLEEP_T);
+  wifi_fpm_open();
+  wifi_fpm_do_sleep(0xFFFFFFF);
+}
+
+void loop() {
+#define TEST(name, var, varinit, func) \
+  static decltype(func) var = (varinit); \
+  if ((var) != (func)) { var = (func); Serial.printf("**** %s: ", name); Serial.println(var); }
+
+#define DO(x...) Serial.println(F( #x )); x; break
+
+  TEST("Free Heap", freeHeap, 0, ESP.getFreeHeap());
+  TEST("WiFiStatus", status, WL_IDLE_STATUS, WiFi.status());
+  TEST("STA-IP", localIp, (uint32_t)0, WiFi.localIP());
+  TEST("AP-IP", apIp, (uint32_t)0, WiFi.softAPIP());
+
+  switch (Serial.read()) {
+    case 'F': DO(WiFiOff());
+    case 'N': DO(WiFiOn());
+    case '1': DO(WiFi.mode(WIFI_AP));
+    case '2': DO(WiFi.mode(WIFI_AP_STA));
+    case '3': DO(WiFi.mode(WIFI_STA));
+    case 'R': DO(if (((GPI >> 16) & 0xf) == 1) ESP.reset() /* else must hard reset */);
+    case 'd': DO(WiFi.disconnect());
+    case 'b': DO(WiFi.begin());
+    case 'B': DO(WiFi.begin(SSID, PSK));
+    case 'r': DO(WiFi.reconnect());
+    case 'c': DO(wifi_station_connect());
+    case 'a': DO(WiFi.setAutoReconnect(false));
+    case 'A': DO(WiFi.setAutoReconnect(true));
+    case 'n': DO(WiFi.setSleepMode(WIFI_NONE_SLEEP));
+    case 'l': DO(WiFi.setSleepMode(WIFI_LIGHT_SLEEP));
+    case 'm': DO(WiFi.setSleepMode(WIFI_MODEM_SLEEP));
+    case 's': DO(WiFi.config(staticip, gateway, subnet));
+    case 'D': DO(wifi_station_dhcpc_start());
+  }
+}
diff --git a/tools/sdk/lib/liblwip2.a b/tools/sdk/lib/liblwip2.a
index e681bdc398..9bfbf64aae 100644
Binary files a/tools/sdk/lib/liblwip2.a and b/tools/sdk/lib/liblwip2.a differ
diff --git a/tools/sdk/lib/liblwip2_1460.a b/tools/sdk/lib/liblwip2_1460.a
index 8929c2d009..56588f6dd4 100644
Binary files a/tools/sdk/lib/liblwip2_1460.a and b/tools/sdk/lib/liblwip2_1460.a differ
diff --git a/tools/sdk/lwip2/Makefile b/tools/sdk/lwip2/Makefile
index 6284486a7c..90d157270e 100644
--- a/tools/sdk/lwip2/Makefile
+++ b/tools/sdk/lwip2/Makefile
@@ -2,6 +2,16 @@
 all install clean: builder/lwip2-src/README
 	make -C builder -f Makefile.arduino $@
 
+latestmaster: downloadmaster install
+
+latestupstream: downloadupstream install
+
+downloadupstream: downloadmaster
+	cd builder/lwip2-src; git checkout master
+
+downloadmaster: download
+	cd builder; git checkout master
+
 download: builder/lwip2-src/README
 
 builder/lwip2-src/README:
diff --git a/tools/sdk/lwip2/README.md b/tools/sdk/lwip2/README.md
index 4063071013..8f17da128b 100644
--- a/tools/sdk/lwip2/README.md
+++ b/tools/sdk/lwip2/README.md
@@ -1,5 +1,9 @@
 ```make install```: download, compile, install lwip2
 
+```make latestmaster```: download latest lwip2, compile, install
+
+```make latestupstream```: download latest lwip2 and latest upstream lwIP, compile, install
+
 ```make download```: download lwIP-2 builder
 
 ```make clean```: clean builder only
@@ -10,4 +14,4 @@ MSS values are in builder/Makefile.arduino
 
 MSS values in boards.txt are only informative
 
-current lwip2 submodule repository: https://github.com/d-a-v/esp82xx-nonos-linklayer/tree/arduino-2.4.0
+current lwip2 submodule repository: https://github.com/d-a-v/esp82xx-nonos-linklayer/tree/arduino-2.4.1
diff --git a/tools/sdk/lwip2/builder b/tools/sdk/lwip2/builder
index a376280e35..2b827f8429 160000
--- a/tools/sdk/lwip2/builder
+++ b/tools/sdk/lwip2/builder
@@ -1 +1 @@
-Subproject commit a376280e3567dff7d494d6fe3e54146f6125f5c6
+Subproject commit 2b827f842925b2daf12b67ab1ae498e58174124e
diff --git a/tools/sdk/lwip2/include/gluedebug.h b/tools/sdk/lwip2/include/gluedebug.h
index 55d0e8d746..0252666524 100644
--- a/tools/sdk/lwip2/include/gluedebug.h
+++ b/tools/sdk/lwip2/include/gluedebug.h
@@ -2,6 +2,7 @@
 #ifndef __GLUE_DEBUG_H
 #define __GLUE_DEBUG_H
 
+// this file is commonly included by both sides of the glue
 /////////////////////////////////////////////////////////////////////////////
 // user-definable
 
@@ -27,6 +28,15 @@
 #define LWIP_DBG_TYPES_ON	(LWIP_DBG_ON)
 #endif
 
+/////////////////////////////////////////////////////////////////////////////
+// packet capture callback from esp side
+#include <stdlib.h>
+
+#ifdef __cplusplus
+extern "C"
+#endif
+void (*phy_capture) (int netif_idx, const char* data, size_t len, int out, int success);
+
 /////////////////////////////////////////////////////////////////////////////
 
 #if UDEBUG && UDEBUGSTORE
diff --git a/tools/sdk/lwip2/include/lwip-git-hash.h b/tools/sdk/lwip2/include/lwip-git-hash.h
index 2d1392e4e5..19bd78b941 100644
--- a/tools/sdk/lwip2/include/lwip-git-hash.h
+++ b/tools/sdk/lwip2/include/lwip-git-hash.h
@@ -1,5 +1,5 @@
 // generated by makefiles/make-lwip2-hash
 #ifndef LWIP_HASH_H
 #define LWIP_HASH_H
-#define LWIP_HASH_STR "STABLE-2_0_3_RELEASE/glue:arduino-2.4.1"
+#define LWIP_HASH_STR "STABLE-2_0_3_RELEASE/glue:arduino-2.4.1-7-g2b827f8"
 #endif // LWIP_HASH_H
diff --git a/tools/sdk/lwip2/include/lwipopts.h b/tools/sdk/lwip2/include/lwipopts.h
index 9d365498d6..1c9d0a9e0f 100644
--- a/tools/sdk/lwip2/include/lwipopts.h
+++ b/tools/sdk/lwip2/include/lwipopts.h
@@ -2688,9 +2688,11 @@
  * Return ERR_OK if packet is accepted, any error code otherwise.
  * Payload points to ethernet header!
  */
-#ifdef __DOXYGEN__
-#define LWIP_HOOK_UNKNOWN_ETH_PROTOCOL(pbuf, netif)
-#endif
+//#ifdef __DOXYGEN__
+//#define LWIP_HOOK_UNKNOWN_ETH_PROTOCOL(pbuf, netif)
+//#endif
+#define LWIP_HOOK_UNKNOWN_ETH_PROTOCOL(pbuf, netif) lwip_unhandled_packet((pbuf), (netif))
+
 /**
  * @}
  */
@@ -3003,4 +3005,12 @@
 #include "lwip-git-hash.h"
 #include <sys/time.h> // settimeofday() + struct timeval
 
+// allow to handle special packets (user redefinable)
+struct pbuf;
+struct netif;
+#ifndef LWIP_ERR_T
+#define LWIP_ERR_T s8
+#endif
+LWIP_ERR_T lwip_unhandled_packet (struct pbuf* pbuf, struct netif* netif) __attribute__((weak));
+
 #endif // MYLWIPOPTS_H